Method and system for delivery of therapeutic gas to a patient and for filling a cylinder

ABSTRACT

A system for filling a portable cylinder with therapeutic gas, and providing therapeutic gas to a patient. Therapeutic gas delivery to a patient may be through a conserver, or may be in a continuous mode. Some embodiments of the invention may test the contents of the portable cylinder prior to filling. The specification also discloses a silent mode of operation where therapeutic gas is provided from the system by means of internal and/or external cylinders.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional application Ser. No.60/421,375 filed Oct. 24, 2002, which application is incorporated byreference herein as if reproduced in full below.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention are directed to creation oftherapeutic gas, possibly for delivery to a patient for respiratory use.More particularly, embodiments of the invention are directed to systemsfor creation of therapeutic gas for delivery to a patient and forfilling portable cylinders for ambulatory use.

2. Background of the Invention

Many patients with lung and/or cardiovascular problems may be requiredto breathe therapeutic gas in order to obtain sufficient dissolvedoxygen in their blood stream. So that these patients may be ambulatory,therapeutic gas may be delivered from a portable cylinder. A portablecylinder may, however, provide only limited volume, and therefore willperiodically need to be refilled. While it is possible to have thesecylinders exchanged or refilled by way of commercial home health careservices, some patients have systems within their homes which perform adual function: filling portable cylinders with oxygen therapeutic gas;and providing therapeutic gas to the patient for breathing. Systems suchas these have come to be known as “trans-fill” systems.

U.S. Pat. No. 5,858,062 to McCulloh et al. (assigned to Litton Systems,Inc., and thus hereinafter the “Litton patent”) may disclose a systemwhere atmospheric air may be applied to a pressure swing absorption(PSA) system which removes nitrogen from the air and thereby increasesthe oxygen content, e.g to approximately 90% or above. In the Littonpatent, oxygen-enriched gas exiting the PSA system may couple to apatient outlet and a pressure intensifier. The pressure of enriched gassupplied by the PSA system may be regulated (in this case lowered)before being provided to a patient. Likewise, the pressure of theenriched gas from the PSA system may be increased by the intensifier forfilling the cylinder. Thus, in the Litton patent, the enriched gasproduct of the PSA system is separated into two streams (outlets in theterminology of the Litton patent) each having the same pressure. TheLitton patent may also disclose the use of an oxygen sensor to monitorthe enriched gas exiting the PSA system. However, the Litton patentdiscloses only monitoring oxygen content of the enriched gas exiting thePSA system, and situations where the oxygen content may be correct butthe enriched gas product contains other harmful chemicals and/or gasesmay not be detected.

U.S. Pat. No. 6,393,802 to Bowser et al. (hereinafter the “Dowserpatent”) may disclose an oxygen concentrator that is adapted to supplytherapeutic gas to the patient and/or to a cylinder filler, whichcylinder filler is controlled to automatically fill a portable cylinder.Much like the Litton patent, the Bowser patent discloses an enriched gasproduct from an oxygen concentrator split into a first stream providedto a compressor (which may then be provided to fill a cylinder), and asecond stream provided to a patient (possibly after proceeding through aflow regulator). The Bowser patent also discloses that prior to fillinga cylinder, the gas pressure of the portable cylinder should bemeasured. If the gas pressure of the portable cylinder is below apredetermined safe minimum, the cylinder is not filled. The Bowserpatent indicates this may be desirable because a cylinder having verylittle residual gas pressure may have been left open and the interior ofthe cylinder may have become contaminated.

U.S. Pat. No. 6,446,630 to Todd, Jr. (hereinafter the “Todd patent”) maydisclose a system where an enriched gas stream exiting an oxygenconcentrator is selectively delivered to a patient (at least during aportion of the patient's inhalation) and the remainder of the timedelivered to a cylinder filler. The Todd patent also mentions the use ofan oxygen sensor to test the enriched gas from the oxygen concentratorprovided to the patient, but fails to discuss the possibility that whileoxygen concentration levels may be correct, other, harmful, gases may bepresent.

Thus, what is needed in the art is a method and related system that moreclosely monitors the therapeutic gas. Further, what is needed is amethod and related system that more efficiently provides the therapeuticgas to a patient.

BRIEF SUMMARY OF SOME OF THE PREFERRED EMBODIMENTS

The problems noted above are solved in large part by a method and systemfor delivery of therapeutic gas to a patient and for filling of acylinder. One exemplary embodiment may be a trans-fill system thatcomprises an intensifier (operable to increase pressure of therapeuticgas provided at an inlet of the intensifier to create a compressedtherapeutic gas stream), a conserver coupled to the compressedtherapeutic gas stream (operable to deliver a bolus of therapeutic gasduring inhalation of the patient), a patient port coupled to theconserver (operable to provide the bolus of therapeutic gas to thepatient), and a cylinder connector (operable to couple a portablecylinder to the compressed therapeutic gas stream). The trans-fillsystem itself may be operable to provide therapeutic gas to the cylinderconnector to fill the portable cylinder while providing therapeutic gasto the patient through the conserver.

In other exemplary embodiments, contents of the connected cylinder maybe tested prior to filling to determine whether impurities may bepresent. In some embodiments, if impurities are present, the connectedcylinder may be evacuated, possibly by a compressor of an attachedoxygen concentrator. In yet other embodiments, therapeutic gas deliveredfrom a source such as an oxygen concentrator may be delivered in acontinuous fashion to a patient by means of a flow meter. In theseembodiments, the continuous flow setting of the flow meter may besensed, and this sensed setting may be used to set bolus deliverythrough the conserver.

In yet other embodiments, additional therapeutic gas cylinders may beprovided, and therapeutic gas may be provided to a patient by theseadditional cylinders without operating an oxygen concentrator and/orintensifier, and thus operation may be substantially silent.

The disclosed devices and methods comprise a combination of features andadvantages which enable it to overcome the deficiencies of the prior artdevices. The various characteristics described above, as well as otherfeatures, will be readily apparent to those skilled in the art uponreading the following detailed description, and by referring to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of the preferred embodiments of theinvention, reference will now be made to the accompanying drawings inwhich:

FIG. 1 illustrates a system for filling portable cylinders in accordancewith at least some embodiments of the invention;

FIG. 2 illustrates a trans-fill system in accordance with at least someembodiments of the invention;

FIG. 3 illustrates a trans-fill system having a continuous deliverycapability in accordance with at least some embodiments of theinvention; and

FIG. 4 illustrates a cross-sectional view of an exemplary flow meterconstructed in accordance will at let some embodiments of the invention.

NOTATION AND NOMENCLATURE

Certain terms are used throughout the following description and claimsto refer to particular system components. This document does not intendto distinguish between components that differ in name but not function.

In the following discussion and in the claims, the terms “including” and“comprising” are used in an open-ended fashion, and thus should beinterpreted to mean “including, but not limited to . . . ”. Also, theterm “couple” or “couples” is intended to mean either an indirect ordirect connection. Thus, if a first device couples to a second device,that connection may be through a direct connection, or through anindirect connection via other devices and connections.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a system for filling portable cylinders in accordancewith at least some embodiments of the invention. Devices such asillustrated in FIG. 1 may be used, for example, in a patient's home tofill portable oxygen cylinders for ambulatory use. In particular, thesystem 100 may comprise an oxygen concentrator 10. The oxygenconcentrator 10 may be any suitable device for increasing the oxygencontent of therapeutic gas delivered to a patient. For example, theoxygen concentrator 10 may be a pressure swing absorption (PSA) systemhaving a plurality of molecular sieve beds operated in a parallelrelationship. Atmospheric air, possible drawn through the air inlet 12,may be drawn or pumped through a first molecular sieve bed wherenitrogen molecules are trapped, and where oxygen and argon moleculesflow through substantially unimpeded. By removing the nitrogen fromatmospheric air, the concentration of oxygen in the gas exiting thesieve bed may be relatively high, e.g. 90% oxygen or more. Gas exiting apressure swing absorption system may be referred to as oxygen-enrichedgas or just enriched gas. The term therapeutic gas may encompass notonly oxygen-enriched gas exiting a pressure swing absorption system, butalso gas having a high therapeutic oxygen content from other sources,such as from liquid oxygen sources. While one molecular sieve bed actsto filter nitrogen, a second molecular sieve bed may use a portion ofthe therapeutic gas as a back-flow gas to flush trapped nitrogen toatmosphere, and prepare the bed for future operation. While a pressureswing absorption system may be the preferred system, any device orsystem capable of making or delivering therapeutic gas may be used.

For the preferred pressure swing absorption system, the pressure of thegas exiting the oxygen concentrator 10 may be on the order of 5-40pounds per square inch (PSI). In order to force the therapeutic gas intoa portable cylinder, for example portable cylinder 14, the pressure ofthe therapeutic gas may need to be increased. Thus, in some embodiments,therapeutic gas exiting the oxygen concentrator 10 may be supplied to anintensifier 16 by way of conduit 18. Intensifier 16 may be any devicewhich is capable of taking the therapeutic gas at a first pressure andincreasing the pressure. Intensifier 16 may be, in effect, a compressorof any available or after-developed type. The intensifier 16 increasesthe gas pressure to about 2200 PSI to create a compressed therapeuticgas system. The compressed therapeutic gas may flow into the cylinder 14by way of conduits 20 and 22 and cylinder connector 21. Cylinderconnector 21 may be any suitable device for coupling a portable cylinderto the system 100 or any of the systems discussed in this specification.The system 100 may stop operation when the portable cylinder 14 is full,possibly determined by a pressure transducer or pressure switch 24coupled to conduit 22. Alternatively, the pressure switch 24 may coupledirectly to the portable cylinder 14.

Summarizing before continuing, a system 100 constructed in accordancewith embodiments of the invention may draw, air at atmospheric pressureinto an oxygen concentrator 10. The oxygen concentrator 10 may enrichthe oxygen content, possibly by removal of nitrogen. Therapeutic gasexiting the oxygen concentrator may be provided to an intensifier whichincreases the pressure, and the therapeutic gas at a higher pressure maybe supplied to the portable cylinder 14.

Although portable cylinders that store therapeutic gas may normallycontain a positive pressure, it is possible for contaminants to enterthe portable cylinders. For example, a patient may leave a portablecylinder open, and when the pressure is exhausted contaminants mayenter. Further, portable cylinders for delivery of therapeutic gas maybe periodically cleaned, and the cleaning solution may remain as acontaminant. According to the related art teachings, if the pressure isbelow a preset threshold, for example 50 PSI, the cylinder should not befilled as it may be contaminated. However, contaminants within acylinder may cause pressure. Thus, while testing the pressure within thecylinder prior to filling may provide some protection fromcontamination, in accordance with at least some embodiments of theinvention the actual contents of the cylinder may be tested prior tofilling the cylinder.

Still referring to FIG. 1, prior to attempting to fill the cylinder (andthus possibly before the oxygen concentrator 10 and intensifier 16become operational), valve 26 may be positioned (possibly automatically)to place the gas sensing device or devices 28 in fluid communicationwith the portable cylinder 14. Pressure within the portable cylinder 14causes gas to move through conduit 22, conduit 30, orifice 32, valve 26,and through the gas sensing device 28, where the gas may be tested.

Gas sensing device 28 may take many forms. In accordance with someembodiments of the invention, the gas sensing device 28 may be anoxygen-selective sensor, such sensors based on zirconium oxide,galvanic, or paramagnetic technologies. If the gas sensing device 28 isan oxygen-selective sensor, the device may analyze the actual percentageof oxygen in the gas. If the oxygen content of the gas falls below apreset threshold, e.g. 85% oxygen, this may be an indication thatcontaminants have entered or have been introduced into the portablecylinder 14.

In alternative embodiments of the invention, the gas sensing device 28may be a time-of-flight density sensor. U.S. Pat. No. 5,060,514 teachesthe use of time-of-flight sensors for measuring density, and thuspurity, of a gas stream. Provisional Application Ser. No. 60/421,375,incorporated by reference above, also teaches a time-of-flight densitysensor which may be used in accordance with embodiments of theinvention. If the gas sense device 28 is a time-of-flight sensor, thedensity of the gas 14 may be indicative of whether contaminants arepresent in the portable cylinder 14.

While using an oxygen-selective senior may provide an indication as tothe percentage of oxygen in the gas, oxygen selective sensors may beunable to detect the type and presence of other, possibly harmful,gases. Likewise with respect to the time-of-flight density sensors, adensity measurement standing alone may not be able to detect thepresence of contaminants, particularly where those contaminants havedensity similar to the therapeutic gas. Thus, in some embodiments thegas sensing device 28 may be a combination of an oxygen-selective sensorand a density sensor. In these embodiments, if the oxygen-selectivesensor determines that the oxygen content is above a predeterminedlevel, such as 85% oxygen, and the density sensor determines that thedensity is within the range expected (the range expected for a highoxygen concentration in combination with mostly argon, as may be theenriched gas product from a pressure swing absorption system), then theportable cylinder 14 may be considered to be contamination free. Thismay be the case even if the initial pressure of the cylinder is belowthe preset limit previously used as an indication of contamination. If,on the other hand, the oxygen-selective sensor indicates that oxygen iswithin normal range, but the density sensor does not indicate a normalreading, this may be an indication that the argon normally present inoxygen-enriched gas may have been replaced with some other, possiblydangerous, gas. Likewise, if the oxygen sensor indicates that the oxygenconcentration is below a predetermined threshold, the portable cylinder14 may not be filled regardless of the density measurement results.

Thus, in accordance with at least some embodiments of the invention, thegas within the portable cylinder 14 may be sampled and analyzed todetermine whether the portable cylinder 14 may be safely filled and usedby a patient independent of its initial pressure.

In the event that a gas sensing device 28 determines prior to fillingthat the portable cylinder 14 is contaminated, in accordance with atleast some embodiments of the invention, system 100 may evacuate thecylinder (pull a vacuum) to remove the contaminants. In particular, anoxygen concentrator 10 in the form of a pressure swing absorption systemmay comprise a compressor 11 that in one aspect compresses air to forceit through a sieve bed, and the compressor may in a second aspect createa vacuum, possibly to remove nitrogen from a sieve bed that is not inoperation. In the event that the cylinder 14 needs to be evacuated, thecompressor 11 within the oxygen concentrator 10 may be utilized toevacuate the gases from the cylinder. In particular, the compressor 11may couple to the oxygen cylinder 14 through conduit 33, valve 34, andconduit 36. The control system (not shown) may activate the compressor11 and open valve 34 to apply vacuum to the portable cylinder 14. Thesteps of evacuating contaminants from the portable cylinder 14 may takemany forms, and the precise mechanism may depend on the type ofcontamination. In some circumstances, simply pulling a vacuum to removethe free gases may be sufficient to remove the contaminants. In othersituations, cyclic at least partial filling followed by evacuation maybe necessary to flush the contaminants. After a sufficient number ofcycles of at least partial filling and pulling a vacuum, the gas sensingdevice or devices 28 may determine that the contaminants have beenremoved, and the portable cylinder may be filled and used for ambulatoryuse.

In addition to sampling the gas within the portable cylinder 14 prior tofilling, a system 100 in accordance with embodiments of the inventionmay also continuously, or periodically, sample gas produced by theoxygen concentrator 10 and/or intensifier 16. Consider a situation wherean initial determination that the portable cylinder 14 is free ofcontaminants has been made, and the oxygen concentrator 10 andintensifier 16 are operational. By selective positioning of valve 26,the gas sense device 28 may sample the therapeutic gas exiting theoxygen concentrator 10. If at any time the gas sense device 28determines that the therapeutic gas is below thresholds for purityand/or contains contaminants, a control system (not specifically shown)may cease production generation and sound an alarm. Likewise, the gassense device 28 may sample the therapeutic gas as it exits theintensifier, again by selective placement of the valve 26.

FIG. 2 illustrates a trans-fill system 200 in accordance withalternative embodiments of the invention. The trans-fill system 200illustrated in FIG. 2 may produce therapeutic gas in a fashion similarto the system illustrated in FIG. 1. Trans-fill system 200 may be usedin locations where a therapeutic gas source is available, e.g. in ahospital where oxygen may be provided in each room. In thesecircumstances, the oxygen concentrator may be omitted from thetrans-fill system 200. Thus, trans-fill system 200 may optionallycomprise an oxygen concentrator 10. The gas sense device 28 may checkthe portable cylinder 14 for contaminants prior to filling. Likewise,gas sense device 28 may check the purity of the therapeutic gas duringnormal operations. If the portable cylinder 14 is found to containcontaminants, or the therapeutic gas used for filling operations isfound to be contaminated, the trans-fill system 200 may soundappropriate alarms and/or stop gas production and/or delivery.Trans-fill system 200 may also have the capability of evacuating theportable cylinder 14, although this ability is not specificallyillustrated in FIG. 2 so as not to unduly complicate the drawing.

In the embodiments illustrated in FIG. 2, the oxygen concentrator 10 andintensifier 16 may provide therapeutic gas to fill cylinder 14, while atthe same time a patient may be provided therapeutic gas. In particular,the portable cylinder 14 may have coupled thereto a regulator 40 whichprovides therapeutic gas from the portable cylinder at a pressure ofbetween approximately 20-25 PSI. The therapeutic gas in the 20-25 PSIrange may then be applied to a conserver 42, which may further regulatepressure of the therapeutic gas, and also senses or anticipates theinhalation cycle of the patient and provides a bolus of gas during theinitial stages of the inhalation to the patient. U.S. Pat. No. 4,612,928to Tiep et al. is exemplary of conserver technology which may be used inaccordance with embodiments of the invention.

Each of the embodiments disclosed in FIGS. 1 and 2 may utilize anintensifier 16. As previously mentioned, the intensifier 16 mayeffectively be a compressor, possibly having air-actuated piston-typecompression chambers. For this reason, the intensifier 16 may emitaudible noise. Likewise, the compressor 11 of the oxygen concentrator 10(if present) may emit audible noise. During daytime use when a patientis awake, the noise that an intensifier 16 and/or compressor 11 of theoxygen concentrator makes may not be a problem. However, duringnight-time use, a patient may be disturbed by the level of audible noisegenerated by the trans-fill system 200. To address potential audiblenoise problems, embodiments of the invention may have a substantiallysilent mode of operation, which may be used at night and at other timeswhen therapeutic gas delivery is desired but where audible noise maypresent problems.

Referring again to FIG. 2 the trans-fill system 200 may optionallycomprise a cylinder 44. Cylinder 44 may be internal or external to thetrans-fill system 200, and may also comprise multiple internal orexternal cylinders or combinations of both. The cylinder 44 may be ofgreater volume than the portable cylinder 14. During operation, thecombination oxygen concentrator 10 and intensifier 16 may fill thecylinder 44. Filling of the cylinder 44 may take place at the same timeas filling the portable cylinder 14, may take place when the portablecylinder 14 is disconnected from the trans-fill system 200, and/or maytake place while providing therapeutic gas to the patient through theregulator 40 and conserver 42. The cylinder 44 preferably has sufficientvolume to supply therapeutic gas to the patient for several hours, e.g.overnight. Thus, during filling of the cylinder 44 (and possibly theportable cylinder 14) the oxygen concentrator 10 and intensifier 16 mayprovide compressed therapeutic gas to the conduit 20. The therapeuticgas may flow through the valve 46, and then into the cylinder 44 throughthe valve 48 and conduit 50. Valve 46 may alternatively be a checkvalve. If filling of cylinder 44 is not desired, valve 48 may be closed.At times when the patient desires a silent operation of the trans-fillsystem 200 (and when cylinder 44 has sufficient stored therapeutic gas),the oxygen concentrator 10 and intensifier 16 may be turned off, andvalve 46 may be closed, thus allowing therapeutic gas within thecylinder 44 to flow through the valve 48 and conduit 50 and onto thepatient port 41 by way of regulator 40 and conserver 42. In someembodiments, cylinder 44 and portable cylinder 14 may contribute todelivery of therapeutic gas during silent operation. As the pressuresupplied to at least the regulator 40 starts to drop, indicating thatthe cylinder 44 and/or portable cylinder 14 may be approaching an emptycondition, this pressure may be detected (e.g. by pressure switch 24),and the oxygen concentrator 10 and intensifier 16 started in order toresume delivery of therapeutic gas.

Much like the discussion above with respect to checking the contents ofthe portable cylinder 14, the gas sense device 28 may also analyze thegas of cylinder 44 prior to filling, and also periodically orcontinuously analyze the therapeutic gas during filling of the cylinder44.

Having a cylinder 44 with a volume larger than that of the portablecylinder 14 also provides the capability for the trans-fill system 200to have a quick-fill feature for the portable cylinder 14. Assume forpurposes of explanation that valve 48 is closed and that the internalcylinder 44 is full or substantially full. To fill the portable cylinder14, the patient may select that the oxygen concentrator and intensifierfill the portable cylinder 14. Filling using the therapeutic gas exitingthe intensifier may be relatively slow, e.g. 2 liters per minute. Thepatient may also select a quick-fill, where the therapeutic gas providedto the cylinder 14 may come solely from the cylinder 44, or possiblyfrom a combination of the oxygen concentrator and intensifier 16 and thecylinder 44. Operation under either of these two circumstances mayprovide for a faster fill of the portable cylinder 14 than may beachieved without the cylinder 44 contributing therapeutic gas.

FIG. 3 illustrates another embodiment of the invention that may becapable of providing a continuous flow of therapeutic gas to the patientas an alternative to providing therapeutic gas from a conserver to thepatient. In particular, the trans-fill system 300 illustrated in FIG. 3may optionally comprise an oxygen concentrator or oxygen source 10. Theoxygen concentrator may be coupled to the intensifier 16 by valve 52.With the valve 52 in a first position (not specifically shown in FIG.3), therapeutic gas exiting the oxygen concentrator 10 may couple to theintensifier 16, where the pressure may be increased for being providedto the cylinder 14 and the regulator 40. In this mode of operation, andmuch like the discussion with respect to FIG. 2, therapeutic gas may beprovided to the patient port 41 from the cylinder 14 and/or intensifier16 through the regulator 40 and conserver 42. Although FIG. 3 does notillustrate an additional cylinder, such as cylinder 44 in FIG. 2, onemay likewise be present. In a second mode of operation, the valve 52 maybe adjusted such that the therapeutic gas exiting the oxygenconcentrator 10 (or other oxygen source) may fluidly couple to a flowmeter 54 (this valve position is illustrated in FIG. 3). In this mode,the intensifier 16 is not provided a stream of therapeutic gas. The flowmeter 54 may take any suitable form, but in accordance with theseembodiments of the invention the flow meter 54 may be a device by whichthe patient may selectively set a continuous flow of oxygen. Forexample, by turning a knob (not specifically shown) on the flow meter54, the patient may select any of a range of possible continuous flows,e.g. half a liter per minute to five liters per minute. Turning the knobmay vary size of an orifice in the therapeutic gas flow stream toprovide the desired outlet volume. The regulated side of the flow meter54 may thus couple to the patient by way of patient port 41.

Thus, embodiments such as illustrated in FIG. 3 may have two modes ofoperation: a continuous flow mode where the user may select the volumeof flow; and a delivery through the conserver, which may provide a bolusof therapeutic gas during inhalation. Although it may be possible toindependently set the continuous flow rate of the flow meter and thebolus delivery of the conserver 42, in accordance with at least someembodiments of the invention the continuous flow setting of the flowmeter may be read by a controller 56. The controller 56, determining orsensing the desired continuous flow rate, may set the conserver flowbased on the continuous flow. For example, the controller 56 may set theconserver to provide a 16.5 milli-liter bolus for every liter per minuteof continuous flow set by the patient. Thus, for a 2 liter-per-minutecontinuous flow, the controller may set the conserver to deliver a 33milli-liter bolus of therapeutic gas, possibly at the beginning of eachinhalation. In this way, the patient may only need to make one flowsetting.

Controller 56 may be any suitable control device, such as, but withoutlimitation, a microcontroller program to perform the desired tasks, amicroprocessor executing programs to perform the desired task, orpossibly some other form of modular controller, such as a programmablelogic controller (PLC). The controller 56 may electrically couple toboth the flow meter 54 and conserver 42, as shown in dashed lines inFIG. 3. Although not specifically shown, the controller 56 may alsoelectrically couple to the oxygen concentrator 10 (if present),intensifier 16, the pressure switch 24 (FIG. 2), and the gas sensedevice or devices 28. Additionally, controller 56 may couple to andcontrol the position of various valves in the system, for example valve26 (FIGS. 1 and 2), valve 34 (FIG. 1), valves 46 and 48 (FIG. 2), andvalve 52 (FIG. 3). Thus, the controller 56 may control each of thesedevices for autonomous operation of the trans-fill system.

FIG. 4 illustrates a cross-sectional view of a flow meter 54 constructedin accordance with embodiments of the invention. In particular, flowmeter 54 may have an inlet port 80 and an outlet port 82. Inlet port 80may have a flange 84, and likewise outlet port 82 may have a flange 86.While FIG. 4 illustrates a flange on both the inlet 80 and outlet 82ports, any suitable connecting mechanism may be used. Inlet port 80 maybe fluidly coupled to inlet chamber 88. Likewise, outlet port 82 may befluidly coupled to an outlet chamber 90. The inlet chamber 88 and outletchamber 90 may be fluidly separated by a cylindrical shaft 92 extendingthrough the body of the flow meter 54. Although not specifically shown,sealing between the inlet and outlet chambers by the cylindrical shaft92 may be by way of gaskets, O-rings, or by close tolerances between thecylindrical shaft 92 and the body of the flow meter 54. Therapeutic gaswithin the inlet chamber 88 and outlet chamber 90 may be substantiallyprevented from escaping to atmosphere way of O-rings 94 and 96. In orderto control the continuous flow of therapeutic gas through the flow meter54, the cylindrical shaft 92 may have a plurality of holes or orificestherethrough of varying sizes. In particular, cylindrical shaft 92 mayhave a first orifice 98 and a second orifice 99. In the illustratedembodiment of FIG. 4, the axis of orifice 98 may be perpendicular to theaxis of orifice 99; however, any number of orifices may be used, and therelationship of their axes need not be perpendicular. As illustrated inFIG. 4, orifice 98 is positioned to allow a continuous flow oftherapeutic gas from the inlet chamber 88 to the outlet chamber 90. Inthe position illustrated in FIG. 4, either one or both of the inlet andthe outlet of orifice 99 may be sealed against the body of the flowmeter 54 (although the sealing is not specifically shown). In order toset a continuous flow of therapeutic gas, a patient may rotate knob 102.Rotation of knob 102 may, for example, place orifice 99 in such aposition that therapeutic gas may flow therethrough. Orifice 99 may beof larger or smaller diameter, and thus provide a different flow of gasthrough the flow meter 54. Rotation of the knob 102 need not necessarilyallow therapeutic gas to flow through only a single orifice. In somepositions knob 102 may allow therapeutic gas to flow through bothorifice 98 and 99. In this circumstance, the total continuous flowthrough the flow meter 54 will be the combination of the flow throughthe orifice 98 and the orifice 99. Although only two orifices 98, 99 areshown, any number of orifices may be used with varying diameters, andwith varying angles between the axes such that turning knob 102 mayallow therapeutic gas to flow through one or more of these orifices tocontrol the continuous flow setting.

Cylindrical shaft 92 preferably also extends below the housing of theflow meter 54. A position-sensing circuit 104 may mechanically couple tothe cylindrical shaft 92 and may be adapted to sense the radial positionof the cylindrical shaft 92. In this way, the position-sensing circuit104 may be able to determine the continuous gas flow setting of the flowmeter 54. Position-sensing circuit 104 may take many forms. In someembodiments, the position-sensing circuit may be a rheostat orpotentiometer whose resistance may be indicative of the radial positionof the cylindrical shaft 92. In alternative embodiments, the sensingcircuit 104 may be a plurality of microswitch devices in operationalrelationship to grooves or flat spots on the outer surface of thecylindrical shaft 92. By actuation of the switches when they come inoperational relationship with the grooves or flat surfaces, the radialposition of the cylindrical shaft 92 may be determined. Regardless ofthe precise mechanism by which the radial position of the cylindricalshaft 92 is made, this information may be coupled to the controller(FIG. 3), and the controller may set the bolus size for the conserver 42using this information.

In the illustrative embodiments of FIG. 4, only the radial position ofthe cylindrical shaft 92 may place one or more orifices in the flowpaths of the continuous flow through the flow meter 54. In alternativeembodiments of the invention, the cylindrical shaft 92 may alsotranslate vertically by turning of knob 102, and this verticaltranslation (possibly in combination with radial translation) may be themechanism by which additional and/or varying size orifices may be placedwithin the flow stream. In these alternative embodiments, theposition-sensing circuit may also sense the vertical position of thecylindrical shaft 92 by any suitable means.

FIG. 3 also illustrates that the gas sense device 28 need notnecessarily couple as illustrated in FIGS. 1 and 2. In particular, thegas sense device 28 may be fluidly coupled to the therapeutic gasdownstream of the flow meter 54, which coupling point is also downstreamof the conserver 42. While it is possible for the gas sense device 28 tooperate continuously, in accordance with at least some embodiments ofthe invention, the gas sense device 28, when sensing therapeutic gasprovided by the oxygen concentrator 10 or exiting the intensifier 16,preferably samples the gas approximately every ten minutes. Operatingthe gas sense device 28 every ten minutes may extend the life of variouscomponents of the gas sense device 28, and in particular may extend thelife of oxygen selective sensors such as the zirconium oxidetechnologies. With the gas sense device 28 coupled as illustrated inFIG. 3, while supplying therapeutic gas to the patient port 41 throughconserver 42 there may be insufficient flow for analysis. Thus, in theseembodiments the system 300 may either: momentarily switch to acontinuous flow mode (by positioning of valve 42) to allow sufficientflow for the gas sense device 28 to operate; or by increasing the bolussize from conserver 42 for sufficient time to allow the gas sense device28 to operate.

Although FIGS. 1-3 illustrate various embodiments of the invention, itshould be noted that features of any of the embodiments not shown in theother figures may be utilized in those alternative embodiments. Forexample, the line 33 of FIG. 1 coupling the compressor 11 of oxygenconcentrator 10 to the cylinder 14 may likewise be used in theembodiments illustrated in FIGS. 2 and 3. Further, the internal cylinder44 illustrated in FIG. 2 may likewise be utilized in the embodimentsillustrated in FIG. 3. Further still, gas sense device 28 may be fluidlycoupled to the systems as illustrated in FIGS. 1 and 2, or alternativelyin FIG. 3. Each of these variations fall within the scope and spirit ofthe invention.

Referring to all the figures generally, it should be understood thateach of the valves may be directly or indirectly controlled by thecontroller 56, though the controller is not shown in all the figures soas not to unduly complicate the drawings. Thus, valve 26 of FIG. 1,which selects a source for testing by gas sense device 28 from theoutlet side of the oxygen concentrator 10 or the outlet side ofintensifier 16, may be controlled by the controller 56. Likewise, thevalve 52 of FIG. 3, that selects operation in a continuous mode orallowing the therapeutic gas exiting the oxygen concentrator 10 toproceed at intensifier 16, may likewise be selectively positioned,directly or indirectly, by the controller 56. Valve 46, which may beclosed during silent operation (and likewise valve 48, which may be openduring silent operation), may be controlled by a controller 56.

The above discussion is meant to be illustrative of the principles andvarious embodiments of the present invention. Numerous variations andmodifications will become apparent to those skilled in the art once theabove disclosure is fully appreciated. It is intended that the followingclaims be interpreted to embrace all such variations and modifications.

1. A trans-fill system comprising: an intensifier operable to increase pressure of therapeutic gas provided from an oxygen concentrator or other source of therapeutic gas, the intensifier creates a compressed therapeutic gas stream; a conserver coupled to the compressed therapeutic gas stream, the conserver operable to deliver a bolus of therapeutic gas during inhalation of a patient; and a cylinder connector operable to couple a portable cylinder to the compressed therapeutic gas stream; wherein the trans-fill system is operable to provide therapeutic gas to the cylinder connector to fill the portable cylinder while providing therapeutic gas to the patient through the conserver.
 2. The trans-fill system as defined in claim 1 further comprising: a gas sense device fluidly coupled to the cylinder connector and receiving a portion of the therapeutic gas of the compressed therapeutic gas stream, the gas sense device operable to detect purity of therapeutic gas; and wherein the trans-fill system is operable to allow a portion of the gas within a connected portable cylinder to flow to the gas sense device, and wherein the trans-fill system refrains from filling the connected portable cylinder if the purity of the gas in the bottle, as determined by the gas sense device, falls below a predetermined threshold.
 3. The trans-fill system as defined in claim 2 wherein the gas sense device further comprises an oxygen-specific sensor.
 4. The trans-fill system as defined in claim 2 wherein the gas sense device further comprises a density sensor.
 5. The trans-fill system as defined in claim 4 wherein the gas sense device further comprises an oxygen-specific sensor.
 6. The trans-fill system as defined in claim 1 further comprising: a cylinder coupled to the compressed therapeutic gas stream; wherein the trans-fill system is operable to provide therapeutic gas from the cylinder when the intensifier is not in operation.
 7. The trans-fill system as defined in claim 6 wherein the cylinder is a cylinder internal to the trans-fill system.
 8. The trans-fill system as defined in claim 6 wherein the cylinder is external to the trans-fill system.
 9. The trans-fill system as defined in claim 8 wherein the cylinder is a portable coupled to the cylinder connector.
 10. A trans-fill system comprising: an intensifier operable to increase pressure of therapeutic gas provided at an inlet of the intensifier to create a compressed therapeutic gas stream; a conserver coupled to the compressed therapeutic gas stream, the conserver operable to deliver a bolus of therapeutic gas during inhalation of a patient; and a cylinder connector operable to couple a portable cylinder to the compressed therapeutic gas stream; a gas sense device fluidly coupled to the cylinder connector, the gas sense device operable to detect purity of therapeutic gas; and a compressor coupled to the cylinder & connector, the compressor operable to evacuate contents of the connected portable cylinder; wherein the trans-fill system is operable to provide therapeutic gas to the cylinder connector to fill the portable cylinder while providing therapeutic gas to the patient through the conserver; wherein the trans-fill system is operable to allow a portion of the gas within a connected portable cylinder to flow so the gas sense device, and wherein the trans-fill system refrains from filling the connected portable cylinder if the purity of the gas in the bottle, as determined by the gas sense device, falls below a predetermined threshold; and wherein the compressor evacuates the connected portable cylinder if the purity detected by the gas sense device falls below the predetermined threshold.
 11. The trans-fill system as defined in claim 10 further comprising: an oxygen concentrator providing therapeutic gas to the intensifier; and wherein the compressor is part of the oxygen concentrator.
 12. The trans-fill system as defined in claim 10 wherein the connected portable cylinder is filled after evacuation.
 13. A trans-fill system comprising: an intensifier operable to increase pressure of therapeutic gas provided at an inlet of the intensifier to create a compressed therapeutic gas stream; a conserver coupled to the compressed therapeutic gas stream, the conserver operable to deliver a bolus of therapeutic gas during inhalation of a patient; and a cylinder connector operable to couple a portable cylinder to the compressed therapeutic gas stream; wherein the trans-fill system is operable to provide therapeutic gas to the cylinder connector to fill the portable cylinder while providing therapeutic gas to the patient through the conserver; a flow meter coupled on a regulated side to a patient port, and wherein when operating the flow meter provides a continuous flow of therapeutic gas to the patient by way of the patient port; a valve coupled between a source of therapeutic gas and the intensifier, the valve selectively couples the source of therapeutic gas to only one of the flow meter and the intensifier; and wherein the trans-fill system provides therapeutic gas to a patient by one of a continuous flow through the flow meter and the bolus delivered by the conserver.
 14. The trans-fill system as defined in claim 13 further comprising: a sense circuit mechanically coupled to the flow meter, the sense circuit operable to detect a flow setting of the flow meter; and a controller electrically coupled to the sense circuit and the conserver; wherein the controller is operable to set a bolus volume for delivery to the patient from the conserver based on the flow setting of the flow meter.
 15. A method comprising: testing gas within a cylinder; evacuating the contents of the cylinder if the gas within the cylinder contains contaminants; compressing a stream of low-pressure therapeutic gas to form a compressed therapeutic gas stream; providing a first portion of the compressed therapeutic gas stream to fill a cylinder; and providing a second portion of the compressed therapeutic gas stream to a patient as a bolus of therapeutic gas.
 16. An apparatus comprising: an intensifier operable to take therapeutic gas at a first pressure and increase the pressure of the therapeutic gas to a second pressure, higher than the first pressure; a fill port fluidly coupled to the therapeutic gas at the second pressure, the fill port operable to selectively couple a cylinder to be filled with therapeutic gas; a gas sense device coupled to the fill port, the gas sense device operable to detect content of gas within the cylinder prior to filling; a compressor coupled to the cylinder connector, the compressor operable to evacuate contents the cylinder; and wherein the compressor evacuates the cylinder if the content of the gas within the cylinder detected by the gas sense device is not suitable for therapeutic use.
 17. The apparatus as defined in claim 16 further comprising: an oxygen concentrator providing therapeutic gas to the intensifier; and wherein the compressor is part of the oxygen concentrator.
 18. A system comprising: a valve having an inlet port fluidly coupled to a source of therapeutic gas at a first pressure, the valve having a first outlet and a second outlet, and wherein the therapeutic gas may be selectively permitted to flow to only one of the first and second outlets; an adjustable flow control device fluidly coupled to the first outlet, the adjustable flow control device operable to create a continuous flow of therapeutic gas at a selected flow rate; an intensifier fluidly coupled to the second outlet, the intensifier operable to produce therapeutic gas at a second pressure higher than the first pressure; a conserver fluidly coupled to the therapeutic gas at the second pressure, the conserver operable to release a bolus of therapeutic gas during a patient inhalation; a patient outlet port fluidly coupled to the adjustable flow control device, and the patient outlet port also fluidly coupled to the conserver; and wherein the volume of therapeutic gas released by the conserver is controlled by the selected flow rate of the adjustable flow device.
 19. The system as defined in claim 18 further comprising: a controller electrically coupled to the adjustable flow control device and the conserver; and wherein the controller is operable to sense a flow rate setting of the adjustable flow control device, and wherein the controller is further operable to set volume of therapeutic gas released by the conserver based on the flow rate setting of the adjustable flow control device. 